Chinese residents who use virtual private networks, or VPNs, to circumvent the country's web blocks have reported difficulties connecting in the past week. A popular VPN provider, Astrill, also cautioned users on March 4 of potential disruptions, a day before China's week-long annual legislative meetings began.

"Due to political meetings in Beijing, VPN access from China may be limited," said a post on Astrill's Twitter account. "We ask for your patience. Thanks for understanding."

Since then, Chinese netizens have reported difficulties with Astrill.

"I only bought Astrill a week ago, and now it's broken," one user wrote on Chinese social network Weibo on Wednesday. "I am regretful when I think about my money."

(Your scribes at China Real Time have also experienced some disruptions in their private VPN use. VPN crackdowns in China generally hit consumer VPNs harder than corporate ones.)

When asked about reports of VPN disruptions on Thursday, Chinese Foreign Ministry spokesman Hong Lei said he wasn't aware of any specifics but that China regulates cyberspace in accordance with law. Astrill didn't immediately respond to an emailed request for comment.

"The Great Firewall" -- the common Western moniker for China's Internet blocks -- conjures up an image of a stationary barrier. But the Wall is fluid. China's Internet restrictions get stricter or looser based on political needs.

When China hosted a global Internet conference in Wuzhen in December, for instance, foreign guests found they had unfettered access to Facebook and other banned websites at the event site.

But during the Hong Kong pro-democracy protests in Sept. 2014, China cut access to Instagram as photos of police using tear gas on students flooded the photo-sharing platform.

China generally keeps one eye open, one eye shut when it comes to VPNs. Foreign-run VPNs are technically illegal in the country. But China's leaders do recognize that the country's innovators need to know what goes on outside its borders if they want to develop globally competitive products.

And it's a small subset of Chinese citizens who are web-savvy enough to subscribe to VPN services in the first place -- since the websites of major VPN providers are blocked in China. Harvard University's Berkman Center for Internet and Society estimated in 2010 that no more than 3% of people in countries with significant web filtering use circumvention tools.

VPNs in China have gone through similar outages in the past, such as in Jan. 2015, when an upgrade to the country's web filters made the blocking of such services more automatic and dynamic.